In an integrated circuit design process, a circuit schematic of an integrated circuit being designed is generated first, for example, in a schematic editor. A pre-layout simulation is performed on the circuit schematic to simulate a performance of the integrated circuit. Since the layout of the integrated circuit has not yet been created at the time the pre-layout simulation is performed, layout-dependent effects (LDEs) of the layout of the integrated circuit cannot be taken into account in the pre-layout simulation. Instead, in the pre-layout simulation, default values of the LDEs are assumed.
Following the pre-layout simulation, the layout of the integrated circuit is generated, for example, using a layout editor. A design verification is then performed on the layout, wherein the design verification includes an LDE parameter extraction, for example.
A post-layout simulation is then performed on the layout. In the post-layout simulation, the LDEs are taken into account, so that the generated circuit performance parameters reflect the actual circuit more accurately. The circuit performance parameters are then compared to the design specification. If the circuit performance parameters meet the requirement of the design specification, the design can be approved. Otherwise, the design process loops back to the schematic generation and editing steps, and the steps including the pre-layout simulation, the layout creation, the design verification, and the post-layout simulation are repeated to modify the design. The loop is repeated until the circuit performance parameters meet the requirement of the design specification.